This is a single-center, double-blind, randomized trial utilizing a three-period, balanced block design, with each period comprising a unique study product administration. The treatments studied are PBF-680 5 mg, PBF-680 20 mg and placebo, as an orally administered capsule. The study includes a screening visit, a selection visit, three visits for the randomized treatment sequence, and an end-of-study follow-up visit, spanning through a 65-day maximum study duration. The study will be conducted on 18 male or female adults aged ³18 years, with a diagnosis of stable, mild to moderate asthma as per GINA guidelines, with no smoking or less than a 5 packs-years smoking history history, responsive to AMP airway challenge as determined in the selection visit.